The act of writing on someone's Facebook wall, poking them, or sending them a Bumper Sticker after seeing them or hanging out with them, often to make light of a joke or incident from the hang-out session. Usually pointless, but creates excitement in the form of a new notification.

Girl #1: Matt and I played frisbee together earlier today, and usually he writes on my wall after we hang out. I'm wondering what I did wrong.
Girl #2: What? No Facebook follow-up?
Mother: Kids these days and their inorganic methods of communication.

The conversation that happens at work or school the day after a particularly significant status message is posted—referring to the content and either remarking on its wittiness or asking for more details. Can lead to awkward situations if someone in the near vicinity of the facebook followup is not a friend of the person who made the post.

Kyle: Man I wish Marla hadn't refused my friend request. She and Tim were having a facebook followup at the water cooler this morning and I had no idea what they were talking about.